Method for producing a chemically adsorbed film

ABSTRACT

According to the present invention, a method for producing a chemically adsorbed film is provided. The method includes the steps of: irradiating a surface of a polymer substrate with ultraviolet laser light so as to produce a hydrophilic group on the surface of the polymer substrate; and contacting a chemical adsorption solution containing a chlorosilane-based chemical adsorbent and a nonaqueous solvent and the polymer substrate on which the hydrophilic group is produced; and reacting the hydrophilic group of the polymer substrate with a chlorosilyl group of the chlorosilane-based chemical adsorbent for forming a covalent bond, thereby forming a chemically adsorbed film on the surface of the polymer substrate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for producing a chemicallyadsorbed film. More specifically, the present invention relates to amethod for producing a chemically adsorbed film which may be provided asa monomolecular film on the surface of a polymer substrate and is usefulin modifying the surface of the substrate.

2. Description of the Related Art

A conventional method for producing a chemically adsorbed film isdisclosed, for example, in Japanese Patent Publication No. 5-16087.According to the method disclosed in the patent publication, achemically adsorbed film is formed on the surface of a substrate byallowing hydrophilic groups such as hydroxyl groups on the surface of asubstrate to react with a chlorosilane surfactant. In the came of usinga substrate where a large number of hydrophilic groups such as hydroxylgroups do not exist on the surface of a substrate, the following methodis known from Japanese Laid-Open Patent Publication No. 6-200074. Forexample, the surface of the substrate is oxidized so as to behydrophilic; and then a chlorosilane surfactant is chemically adsorbedonto the surface by performing an oxygen plasma treatment, a coronatreatment, a UV light irradiation using a low-pressure mercury lamp, animmersion of the substrate in a chromic acid mixture (a mixed solutionof concentrated sulfuric acid and potassium bichromate), or the like.

According to these conventional methods, however, even when oxidizationis performed, satisfactory effects cannot be obtained, and a sufficientamount of hydrophilic groups (e.g., hydroxyl groups) requires forreacting with a chlorosilane surfactant cannot be produced on thesurface of a substrate. As a result, a chemically adsorbed film cannotbe formed on the surface of the substrate at all, and even if the filmcan be formed, a high-density chemically adsorbed film cannot beobtained because there are many pin holes in the resulting film.Therefore, neither a chemically adsorbed film having satisfactoryproperties, e.g., water repellency, oil repellency, anti-contaminatingproperty, antistatic property and the like, nor a chemically adsorbedfilm having practical durability can be obtained.

In addition, according to the above-described methods, since a desiredpart of the surface of the substrate cannot be selectively oxidized, itis impossible to obtain a chemically adsorbed film on which desired finepatterns are formed.

Therefore, a method for producing a high-density chemically adsorbedfilm and a method for producing a chemically adsorbed film havingdesired fine patterns thereon are required to be developed.

SUMMARY OF THE INVENTION

According to the present invention, a method for producing a chemicallyadsorbed film in provided. The method includes the steps of: irradiatinga surface of a polymer substrate with ultraviolet laser light so as toproduce a hydrophilic group on the surface of the polymer substrate; andcontacting a chemical adsorption solution containing achlorosilane-based chemical adsorbent and a nonaqueous solvent and thepolymer substrate on which the hydrophilic group is produced; andreacting the hydrophilic group of the polymer substrate with achlorosilyl group of the chlorosilane-based chemical adsorbent forforming a covalent bond, thereby forming a chemically adsorbed film onthe surface of the polymer substrate.

In one embodiment, the ultraviolet laser light is selectively irradiatedonto a predetermined part of the surface of the polymer substrate.

In another embodiment, the polymer substrate is made of a materialselected from the group consisting of: polyimide, polycarbonate,polysulfone, polyethyleneterephthalate, polyetheretherketone,polyarylate, polyethersulfone, and polyetherimide.

In still another embodiment, the ultraviolet laser light is excimerlaser light.

In still another embodiment, the chlorosilane-based chemical adsorbenthas a fluorocarbon group.

According to another aspect of the present invention, a method forproducing a chemically adsorbed film is provided. The method includesthe steps of: irradiating a surface of a polymer substrate withultraviolet light including a wavelength of about 175 nm or less so asto produce a hydrophilic group on the surface of the polymer substrate;and contacting a chemical adsorption solution containing achlorosilane-based chemical adsorbent and a nonaqueous solvent and thepolymer substrate on which the hydrophilic group is produced; andreacting the hydrophilic group of the polymer substrate with achlorosilyl group of the chlorosilane-based chemical adsorbent forforming a covalent bond, thereby forming a chemically adsorbed film onthe surface of the polymer substrate.

In one embodiment, the ultraviolet light including a wavelength of about175 nm or less is selectively irradiated onto a predetermined part ofthe surface of the polymer substrate.

Thus, the invention described herein makes possible the advantages of(1) providing a method for producing a high-density chemically adsorbedfilm; (2) providing a method for producing a chemically adsorbed filmhaving excellent properties such as water/oil repellencies,anti-contaminating property, and antistatic property; (3) providing amethod for producing a chemically adsorbed film having excellentdurability; and (4) providing a method for producing a chemicallyadsorbed film having desired fine patterns thereon.

These and other advantages of the present invention will become apparentto those skilled in the art upon reading and understanding the followingdetailed description with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1E are schematic illustrations showing the respective stepsof an exemplary method for producing a chemically adsorbed filmaccording to the present invention, in which:

FIG. 1A is a schematic cross-sectional view of a substrate;

FIG. 1B is a schematic illustration showing a step of producinghydrophilic groups on the surface of the substrate;

FIG. 1C is a schematic illustration showing a step of forming achemically adsorbed film on the surface of the substrate shown in FIG.1B where the hydrophilic groups are produced;

FIG. 1D is a schematic illustration showing a step of producing an evenlarger number of hydrophilic groups on the surface of the substrate; and

FIG. 1E is a schematic illustration showing a step of forming achemically adsorbed film on the surface of the substrate shown in FIG.1D where an even larger number of hydrophilic groups have been produced.

FIGS. 2A to 2C are schematic illustrations showing the respective stepsof another exemplary method for producing a chemically adsorbed filmaccording to the present invention, in which:

FIG. 2A is a schematic illustration showing a step of selectivelyirradiating a desired part of the surface of the substrate with UV light(UV laser and/or UV light including a wavelength of about 175 nm orless);

FIG. 2B is a schematic illustration showing the hydrophilic groupsselectively formed in the desired part of the surface of the substrate;and

FIG. 2C is a schematic illustration showing the chemically adsorbed filmselectively formed in the desired part of the surface of the substrate.

FIG. 3 is an ESCA chart of the chemically adsorbed film obtained by theproduction method according to the present invention.

FIG. 4 is an ESCA chart of the chemically adsorbed film obtained in thecomparative examples.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred method for producing a chemically adsorbed film according tothe present invention will be described with reference to FIGS. 1A to1E.

FIG. 1A is a schematic cross-sectional view of a substrate 11. Thesubstrate 11 is made of a polymer material. As the polymer material forthe substrate 11, any of known polymer materials widely used can beemployed. However, the present invention is directed to polymer resinmaterials having no hydrophilic groups, in particular. Such polymermaterials include polyimide, polycarbonate, polyethyleneterephthalate,polyethersulfone, polyetheretherketone, polyarylate, polysulfone,polyetherimide, and the like. These polymer materials can be used forthe substrate in any desired shapes (for example, film, plate, othercomplex shapes).

Then, as shown in FIG. 1B, a large number of hydrophilic groups, e.g.,OH groups 12 and NH groups 13, are produced on the surface of thesubstrate 11. The hydrophilic groups are produced by irradiating thesurface of the substrate with UV laser or UV light including awavelength of 175 nm or less. As the UV laser, excimer lasers such as anArF laser (wavelength: 193 nm), a KrF laser (wavelength: 248 nm), and anXeCl laser (wavelength: 308 nm); gas lasers such as an He-Cd laser(wavelength: 325 nm), an Ar laser (wavelength: 351.1 to 363.8 nm), andan N_(z) laser (wavelength: 337 nm); or the harmonic wave of a YAG laser(wavelength: 266 nm, for example) can be used. An excimer laser ispreferably used, because the excimer laser is a high-output short-pulselaser and therefore excellent both in reactivity and controllability.

As a UV light source for emitting UV light including a wavelength of 175nm or less, a dielectric barrier discharge-lamp is generally used. Forexample, in the case of the dielectric barrier discharge lamp in whichXe gas is enclose, the central wavelength of the emitted UV light is 172nm. Since the optical absorption coefficient of oxygen is high at thiswavelength, the concentration of resulting ozone and the concentrationof excited oxygen atoms become higher and the effects obtained byoxidizing the substrate increase. As a result, a large number ofhydrophilic groups are produced on the surface of the substrate.

The conditions for irradiating the UV light (UV laser and/or UV lightincluding a wavelength of 175 nm or less) are variable depending uponthe kind of UV light used. For example, in the case of irradiating anexcimer laser, the laser is preferably irradiated at an energy densityin an approximate range of 0.01 to 10 J/cm² for every pulse irradiation,and more preferably at an energy density in an approximate range of 0.1to 1 J/cm² for every pulse irradiation. By irradiating the UV light atan energy density in such a range, the irradiated part of the substrateis instantaneously decomposed, so that an abrasion occurs. As a result,a large number of hydrophilic groups are produced on the surface of thesubstrate. For example, in the case of using an Xe gas dielectricbarrier discharge lamp, the illuminance of the lamp is preferably in anapproximate range of 5 to 100 mW/cm², and more preferably in anapproximate range of 20 to 50 mW/cm². The irradiation time is preferablyin a range of about 5 to about 10 minutes, more preferably in a range ofabout 6 to about 8 minutes.

Next, as shown in FIG. 1C, a chemically adsorbed film 16 is formed inthe following procedure. (Steps (A) and (B)).

(A) A chemical adsorption solution containing a chlorosilane-basedchemical adsorbent and a nonaqueous solvent is made to come into contactwith the substrate on which the hydrophilic groups have been produced.As the chlorosilane-based chemical adsorbent contained in the chemicaladsorption solution, trichlorosilane-based chemical adsorbent such asCF₃ (CF₂)₇ (CH₂)₂ SiCl₃, CF₃ CH₂ O(CH₂)₁₅ SiCl₃, CF₃ (CH₂)₂ Si(CH₃)₂(CH₂)₁₅ SiCl₃, CF₃ (CF₂)₃ Si(CH₃)₂ (CH₂)₉ SiCl₃, CF₃ (CF₂)₇ Si(CH₃)₂(CH₂)₈ SiCl₃, CF₃ (CF₂)₇ Si(CH₃)₂ (CH₂)₁₀ SiCl₃, CF₃ COO(CH₂)₁₅ SiCl₃and CF₃ (CF₂)₅ (CH₂)₂ SiCl₃, and monochlorosilane-based ordichlorosilane-based chemical adsorbent substituted by a lower alkylgroup such as CF₃ (CF₂)₇ (CH₂)₂ SiCl_(n) (CH₃)_(3-n), CF₃ (CF₂)₇ (CH₂)₂SiCl_(n) (C₂ H₅)_(3-n), CF₃ CH₂ O(CH₂)₁₅ SiCl_(n) (CH₃)_(3-n), CF₃ CH₂O(CH₂)₁₅ SiCl_(n) (C₂ H₅)_(3-n), F₃ (CH₂)₂ Si(CH₃)₂ (CH₂)₁₅ SiCl_(n)(CH₃)_(3-n), CF₃ (CH₂)₂ Si(CH₃)₂ (CH₂)₁₅ SiCl_(n) (C₂ H₅)_(3-n), CF₃(CF₂)₇ Si(CH₃)₂ (CH₂)₈ SiCl_(n) (CH₃)_(3-n), CF₃ COO(CH₂)₁₅ SiCl_(n)(CH₃)_(3-n) and CF₃ (CF₂)₅ (CH₂)₂ SiCl_(n) (CH₃)_(3-n) (in all theabove-cited compounds, n is 1 or 2) can be used. A trichlorosilane-basedchemical adsorbent is preferably used, because SiCl bonds, excluding theSiCl bonds forming covalent bonds (e.g., --Si--O-- bonds), with ahydrophilic group can further form covalent bonds (e.g., --Si--O--bonds) with adjacent SiCl bonds, and a more solid chemically adsorbedfilm can be obtained. Among the trichlorosilane-based chemicaladsorbents, a compound represented by a formula CF₃ (CF₂)₈ (CH₂)₂ SiCl₃(where q is preferably about 3 to about 25, more preferably about 6 toabout 15) is particularly preferred because the compound has anexcellent balance among solvent solubility, chemical adsorptiveness andvarious properties such as water/oil repellencies, and,anti-contaminating property.

Any nonaqueous solvent can be used so long as the solvent does not etchthe substrate, and does not include active hydrogens reactive with aSiCl group. Such solvents include carbon-containing solvents such ascyclohexane, hexadecane, isooctane, toluene, xylene, tetralin, petroleumether, chloroform, carbon tetrachloride, perfluorocarbon, perfluoroalkyltertiary-amine, perfluoroalkyl cyclic ether and the like. Theconcentration of the chemical adsorption solution is preferably in anapproximate range of 0.01 to 10 weight %, more preferably in anapproximate range of 0.1 to 5 weight %. As the methods for contactingthe chemical adsorption solution and the substrate, the immersion of thesubstrate in the chemical adsorption solution, spraying and the like canbe used. Immersion is preferred. In performing the immersion, theimmersion time is preferably in an approximate range of 1 minute to 20hours, more preferably in an approximate range of 10 minutes to 6 hours.

(B) By contacting the chemical adsorption solution and the substrate inthe above-described manner (e.g., by immersion), the hydrophilic groupsof the substrate react with the chlorosilyl groups of thechlorosilane-based chemical adsorbent. More specifically, this reactionis a dehydrochloric acid reaction between the OH groups 12, the NHgroups 13, etc. shown in FIG. 1B and the SiCl groups. As a result, thecovalent bonds such as --Si--O-- bonds 14 and --Si--N-- bonds 15 shownin FIG. 1C are formed. The chemically adsorbed film 16 is formed in thisway.

Preferably, the substrate on which the hydrophilic groups are producedis allowed to react with a material including a plurality of SiCl groupsin a molecule, and then allowed to react with water. As a result, alarger number of hydrophilic groups can be produced on the surface ofthe substrate as shown in FIG. 1D. This is because a plurality ofhydrophilic groups are produced with respect to one hydrophilic groupproduced by the UV light (UV laser and/or UV light including awavelength of 175 nm or less) irradiation. The materials having aplurality of SiCl groups in a molecule include SiCl₄, SiHCl₃, Cl--(SiCl₂O)_(n) --SiCl₃ (where n is an integer equal to or larger than 1), Cl_(m)(CH₃)_(3-m) Si--(CH₂)_(p) --SiCl_(m) (CH₃)_(3-m) (where m is an integerin a range of 1 to 3, and p is an integer equal to or larger than 1).The reaction between the material having a plurality of SiCl groups in amolecule and the hydrophilic groups of the substrate is conducted in thesame way as the formation of the chemically adsorbed film mentionedabove.

An exemplary reaction using a material having a plurality of SiCl groupsin a molecule will be described. A substrate on which hydrophilic groups(e.g., OH groups and NH groups) are produced is immersed in a solutioncontaining 1 weight % of SiCl₄ in cyclohexane, for example. As a result,the SiCl bonds of SiCl₄ react with the OH groups and the NH groups onthe surface of the substrate, so that the bonds represented by followingFormula I are formed and a large number of SiCl bonds not reacted withthe OH groups or the NH groups come to exist on the surface of thesubstrate. ##STR1##

By allowing the substrate to further react with water, the large numberof SiCl bonds existing on the surface of the substrate react with thehydroxyl groups of water, so that the bonds represented by followingFormula II are formed. ##STR2##

In this way, an even larger number of OH groups 17 can be produced onthe surface of the substrate as shown in FIG. 1D.

It is possible to further form a chemically adsorbed film on the surfaceof the substrate shown in FIG. 1D. As a result, a higher-densitychemically adsorbed film 18 can be formed as shown in FIG. 1E.

Another preferred method for producing a chemically adsorbed filmaccording to the present invention will be described with reference toFIGS. 2A to 2C. This is a method for forming a chemically adsorbed filmhaving desired fine patterns on the surface of the substrate. Forsimplification, only the specific requirements for selectively producinghydrophilic groups in a desired part of the surface of the substratewill be described.

As shown in FIG. 2A, a metallic mask 22 having an opening 27 with asimilar pattern to that of the desired pattern to be formed on thesurface of the substrate 21 is disposed in an optical path of UV light(UV laser and/or UV light having a wavelength of 175 nm or less). The UVlight passed through the opening 27 is projected onto the substrate 21via a converging lens 23 so as to be enlarged or reduced. As a result,hydrophilic groups can be selectively produced in the desired part ofthe surface of the substrate 21, as shown in FIG. 2B. The UV lightirradiation can be performed with the metallic mask disposed on thesurface of the substrate, or the irradiation can be performed onto asurface of the substrate on which a metallic mask having a desiredpattern is formed by a known method.

By allowing the hydrophilic groups selectively produced in the desiredpart of the surface of the substrate as shown in FIG. 2B to react withthe chlorosilyl groups of the chlorosilane-based chemical adsorbentmentioned above, a chemically adsorbed film 25 is formed in the desiredpart 24 of the surface of the substrate as shown in FIG. 2C. In otherwords, a chemically adsorbed film having a desired fine pattern can beformed.

According to the present invention, by irradiating the surface of thesubstrate with UV laser and/or UV light including a wavelength of about175 nm or less, hydrophilic groups are produced on the surface of thesubstrate. Based on the following mechanism, such particular UV lightcan produce a far larger number of hydrophilic groups on the surface ofthe substrate as compared with the case of irradiating commonly used UVlight. (i) UV laser has a far higher fluence (or a far higher energydensity) as compared with commonly used UV light (e.g., light emittedfrom a low-pressure mercury lamp and the like). Therefore, when thesurface of the substrate is irradiated with UV laser, a large number ofbonds of polymer chains on the surface of the substrate areinstantaneously decomposed, so that a large number of low molecularfragments are produced and then vaporized. A large number of radicalshave been produced in the portion of the surface of the substrate wherethe fragments have been vaporized, and these radicals react with waterin the air, so that a large number of hydrophilic groups are produced.(ii) Since light with a short wavelength (i.e., UV light including awavelength of 175 nm or less) has a high photon energy, it has anexcellent ability for exciting the atoms on the surface of thesubstrate. For example, in the case where the substrate is irradiated inan atmosphere containing oxygen with UV light having a wavelength longerthan 175 nm, oxygen is turned into ozone and then excited oxygen atomsare produced. However, in the case where the substrate is irradiatedwith UV light having a wavelength of 175 nm or less, the excited oxygenatoms are directly produced. In other words, the irradiation of the UVlight including a wavelength of 175 nm or less instantaneously producesa large number of excited oxygen atoms. Since the excited oxygen atomshave an oxidization function (or the function of producing hydrophilicgroups), a large number of hydrophilic groups are produced on thesurface of the substrate irradiated with the UV light including awavelength of 175 nm or less.

Furthermore, according to the present invention, a large number ofhydrophilic groups obtained in the above-described manner and SiClgroups of the chlorosilane-based chemical adsorbent form covalent bonds,thereby forming a chemically adsorbed film. Therefore, the resultingchemically adsorbed film has a high density and is solidly bonded withthe substrate. As a result, it is possible to obtain a chemicallyadsorbed film having excellent durability and excellent properties suchas water repellency, oil repellency, anti-contaminating property andantistatic property resulting from the properties of the-chemicalabsorptive material.

Hereinafter, the present invention will be described by way ofillustrative examples with reference to accompanying drawings. It isnoted that the present invention is not limited to the specific examplesdescribed below.

EXAMPLE 1

A polyimide film (product name: Kapton; manufactured by Du Pont-TorayCo., Ltd.) was used as a substrate, and the surface of the substrate wasirradiated with 50 pulses of ArF laser light at an energy density of 0.5J/cm² for every pulse irradiation. Next, the substrate irradiated withthe laser light was immersed in a solution containing 1 weight % oftetra-chlorosilane (SiCl₄) in cyclohexane for 10 minutes. As a result,the SiCl bonds of tetrachlorosilane reacted with the hydrophilic groupson the surface of the substrate, so that the bonds represented byFormula I were formed over the entire surface of the substrate. Thissubstrate was washed with cyclohexane and then immersed in water, sothat the bonds represented by Formula II were formed and a large numberof OH groups were produced on the surface of the substrate. ##STR3##

Then, a chemical adsorption solution was prepared in which a compoundrepresented by following Formula III as a chlorosilane-based chemicaladsorbent was dissolved in a mixed solvent of hexadecane and chloroformhaving a weight ratio of 80/20 so as to have a concentration of 1 weight%. When the substrate obtained in the above-described manner wasimmersed in this solution for an hour, the SiCl bonds of the compoundrepresented by Formula III reacted with the OH groups on the surface ofthe substrate, so that the bonds represented by following Formula IVwere formed over the entire surface of the substrate. ##STR4##

As a result, a chemically adsorbed film was formed on the surface of thepolyimide film.

The water repellency of the resulting chemically adsorbed film wasestimated. The estimation was conducted based on the criterion of acontact angle between the surface of the substrate and a water drop onthe surface of the substrate. That is to say, the larger the contactangle is, the more satisfactory the water repellency is. The contactangle was measured using the following procedure. Under the conditionswhere the temperature was maintained at room temperature and therelative humidity was set to be in a range of 40 to 60%, water having avolume of 20 μl was dripped onto the surface of the substrate. Thecontact angle is defined as an angle formed between a tangent of a waterdrop and the surface of the substrate at a point where the surface ofthe water drop is in contact with the surface of the substrate. In thiscase, the contact angle is an angle on the side where the water drop isincluded. The contact angle was measured using an automatic contactangle meter (type CA-Z; manufactured by Kyowa Interface Science Co.,Ltd.). The results are shown in following Table 1 together with theresults of Examples 2 to 9 and 11 and Comparative Examples 1 and 2 to bedescribed below.

In the following Examples and Comparative Examples, the chemicallyadsorbed film also contains fluorocarbon groups. Therefore, the densityof the chemically adsorbed film can be estimated based on the degree ofthe water repellency of the film. The more satisfactory the waterrepellency becomes (or the larger the contact angle becomes), the higherthe density of the chemically adsorbed film becomes.

                  TABLE 1                                                         ______________________________________                                        Measurement Results of Contact Angle (degrees)                                           Contact angle (degree)                                             ______________________________________                                        Example 1    123                                                              Example 2    112                                                              Example 3    124                                                              Example 4    118                                                              Example 5    122                                                              Example 6    117                                                              Example 7    120                                                              Example 8    120                                                              Example 10   119                                                              Comparative  58                                                               Example 1                                                                     Comparative  66                                                               Example 2                                                                     Comparative  55                                                               Example 3                                                                     ______________________________________                                    

The surface of the resulting chemically adsorbed film was analyzed by anelectron spectroscopy for chemical analysis (ESCA). The ESCA chart isshown in FIG. 3, and the composition of a surface element together withthe results of Comparative Example 2 to be described later are shown infollowing Table 2.

                  TABLE 2                                                         ______________________________________                                        Composition of Surface Elements (percent)                                                       Comparative                                                            Example 1                                                                            Example 2                                                   ______________________________________                                        C            52.6     72.8                                                    F            27.9     2.8                                                     O            13.1     17.3                                                    Si           2.9      0.7                                                     N            3.5      6.4                                                     ______________________________________                                    

EXAMPLE 2

A polyethyleneterephthalate film (product name: Myler; manufactured byDu Pont Japan Limited) was used as a substrate, and the surface of thesubstrate was irradiated with 20 pulses of KrF laser light at an energydensity of 1 J/cm² for every pulse irradiation. Next, a chemicaladsorption solution was prepared in which the compound represented byfollowing Formula V was dissolved as a chlorosilane-based chemicaladsorbent in cyclohexane so as to have a concentration of 1 weight %.Then, the substrate irradiated with the laser light was immersed in thissolution for an hour. As a result, the SiCl bonds of the compoundrepresented by Formula V reacted with the hydrophilic groups on thesurface of the substrate, so that the bonds represented by followingFormula VI were formed over the entire surface of the substrate.##STR5##

As a result, a chemically adsorbed film was formed on the surface of thepolyethyleneterephthalate film. The resulting chemically adsorbed filmwas subjected to the repellency estimation test. The results of theestimation are also shown in Table 1.

EXAMPLE 3

Polyethersulfone was used for a substrate, and the surface of thesubstrate was irradiated with 20 pulses of KrF laser light at an energydensity of 0.5 J/cm² for every pulse irradiation. Next, a solution wasprepared in which hexachlorodisiloxane (Cl₃ SiOSiCl₃) was dissolved in afluorine-containing solvent (e.g., Fluorinert PF-5080 (product name);manufactured by Sumitomo 3M Ltd.) so as to have a concentration of 1weight %. Then, the substrate irradiated with the laser light wasimmersed in this solution for 10 minutes. As a result, the SiCl bonds ofhexachlorodisiloxane reacted with the hydrophilic groups on the surfaceof the substrate, so that the bonds represented by following Formula VIIwere formed over the entire surface of the substrate. This substrate waswashed with the fluorine-containing solvent and then immersed in water,so that an even larger number of OH groups were produced on the surfaceof the substrate as represented by following Formula VIII. ##STR6##

Then, a chemical adsorption solution was prepared in which a compoundrepresented by Formula III was dissolved in a fluorine-containingsolvent (e.g., Fluorinert FC40 (product name); manufactured by Sumitomo3M Ltd.) so as to have a concentration of 1 weight %. When the substrateobtained in the above-described manner was immersed in this solution foran hour, the SiCl groups of the compound represented by Formula IIIreacted with the hydroxyl groups on the surface of the substrate, sothat the bonds represented by Formula IV were formed over the entiresurface of the substrate. ##STR7##

As a result, a chemically adsorbed film was formed on the surface of thepolyethersulfone substrate. The resulting chemically adsorbed film wassubjected to the repellency estimation test. The results of theestimation are also shown in Table 1.

EXAMPLE 4

A chemically adsorbed film was formed in the same way as in Example 3except that a polycarbonate substrate was used. The resulting chemicallyadsorbed film was subjected to the repellency estimation test. Theresults of the estimation are also shown in Table 1.

EXAMPLE 5

A chemically adsorbed film was formed in the same way as in Example 3except that a polyether- etherketone substrate was used. The resultingchemically adsorbed film was subjected to the repellency estimationtest. The results of the estimation are also shown in Table 1.

EXAMPLE 6

A chemically adsorbed film was formed in the same way as in Example 3except that a polyarylate substrate was used. The resulting chemicallyadsorbed film was subjected to the repellency estimation test. Theresults of the estimation are also shown in Table 1.

EXAMPLE 7

A chemically adsorbed film was formed in the same way as in Example 3except that a polysulfone substrate was used. The resulting chemicallyadsorbed film was subjected to the repellency estimation test. Theresults of the estimation are also shown in Table 1.

EXAMPLE 8

A chemically adsorbed film was formed in the same way as in Example 3except that a polyetherimide substrate was used. The resultingchemically adsorbed film was subjected to the repellency estimationtest. The results of the estimation are also shown in Table 1.

EXAMPLE 9

A polyimide film (product name: Kapton, manufactured by Du Pont-TorayCo., Ltd.) was used as a substrate, and a desired part of the surface ofthe substrate was irradiated with 50 pulses of KrF laser light at anenergy density of 0.5 J/cm² for every pulse irradiation by using themetallic mask shown in FIG. 2. Then, the substrate was immersed in acyclohexane solution containing 1 weight % of hexachlorodisiloxane for10 minutes. As a result, the SiCl groups of hexachlorodisiloxane reactedwith the hydroxyl groups on the surface of the substrate, so that thebonds represented by Formula VII were formed over the entire surface ofthe substrate. This substrate was washed with cyclohexane and thenimmersed in water, so that an even larger number of OH groups wereproduced on the surface of the substrate as represented by Formula VIII.##STR8##

Then, a chemical adsorption solution was prepared in which the compoundrepresented by Formula III was dissolved as a chlorosilane-basedchemical adsorbent in cyclohexane so as to have a concentration of 1weight %. When the substrate obtained in the above-described manner wasimmersed in this solution for an hour, the SiCl groups of the compoundrepresented by Formula III reacted with the OH groups on the surface ofthe substrate, so that the bonds represented by Formula IV wereselectively formed only in the part of the surface of the substrateirradiated with the laser light. ##STR9##

The resulting substrate was immersed in water, and then lifted. As aresult, water was repelled only by the part irradiated with the laserlight. Consequently, it has been confirmed that a chemically adsorbedfilm with the fine pattern has been formed on the surface of thepolyimide film.

EXAMPLE 10

A polyimide film (product name: Kapton; manufactured by Du Pont-TorayCo., Ltd.) was used as a substrate, and an Xe gas dielectric barrierdischarge lamp (product name: UER200-172; manufactured by Ushio Inc.)was used as a light source. The substrate was disposed at a position 10mm away from the light source, and was irradiated using the lamp for 5minutes. Then, the irradiated substrate was immersed in a cyclohexanesolution containing 1 weight t of hexachlorodisiloxane for 10 minutes.As a result, the bonds represented by Formula VII were formed. Thissubstrate was washed with cyclohexane and then immersed in water, sothat an even larger number of OH groups were produced on the surface ofthe substrate as represented by Formula VIII. ##STR10##

Then, a chemical adsorption solution was prepared in which the compoundrepresented by Formula III was dissolved as a chlorosilane-basedchemical adsorbent in cyclohexane so as to have a concentration of 1weight %. When the substrate obtained in the above-described manner wasimmersed in this solution for an hour, the SiCl groups of the compoundrepresented by Formula III reacted with the OH groups on the surface ofthe substrate, so that the bonds represented by Formula IV were formed.

    CF.sub.3 (CF.sub.2).sub.7 (CH.sub.2).sub.2 SiCl.sub.3      (III) ##STR11##

As a result, a chemically adsorbed film was formed on the surface of thepolyimide film. The resulting chemically adsorbed film was subjected tothe repellency estimation test. The results of the estimation are alsoshown in Table 1.

EXAMPLE 11

A polyimide film (product name: Kapton; manufactured by Du Pont-TorayCo., Ltd.) was used as a substrate, a metallic mask was closely attachedto the surface of the substrate, and an Xe gas dielectric barrierdischarge lamp (product name: UER200-172; manufactured by Ushio Inc.)was used as a light source. The substrate was disposed at a position 10mm away from the light source, and was irradiated using the lamp for 5minutes. Then, the substrate irradiated with the lamp was immersed in acyclohexane solution containing 1 weight % of tetrachlorosilane for 10minutes. As a result, the SiCl groups of tetra-chlorosilane reacted withthe hydrophilic groups on the surface of the substrate, so that thebonds represented by Formula I were formed. This substrate was washedwith cyclohexane and then immersed in water, so that the bondsrepresented by Formula II were formed and an even larger number of OHgroups were produced on the surface of the substrate. ##STR12##

Then, a chemical adsorption solution was prepared in which the compoundrepresented by Formula V was dissolved as a chlorosilane-based chemicaladsorbent in cyclohexane so as to have a concentration of 1 weight %.When the substrate obtained in the above-described manner was immersedin this solution for an hour, the SiCl groups of the compoundrepresented by Formula V reacted with the hydrophilic groups on thesurface of the substrate, so that the bonds represented by Formula VIwere selectively formed only in the part of the surface of the substrateirradiated with the light. ##STR13##

The resulting substrate was immersed in water, and then lifted. As aresult, water was repelled only by the part irradiated with the light.Consequently, it has been confirmed that a chemically adsorbed film withthe fine pattern has been formed on the surface of the polyimide film.

Comparative Example 1

A polyimide film (product name: Kapton; manufactured by Du Pont-TorayCo., Ltd.) was used as a substrate, and was immersed in a chloroformsolution containing 1 weight % of tetrachlorosilane (SiCl₄) for 10minutes without performing any treatment therefor. This substrate wasimmersed in the solution, washed with chloroform and then immersed inwater. After the substrate was dried, the substrate was immersed for anhour in a solution in which the compound represented by Formula V wasdissolved in cyclohexane so as to have a concentration of 1 weight %.##STR14##

As a result, a chemically adsorbed film was formed on the surface of thepolyimide film. The resulting chemically adsorbed film was subjected tothe repellency estimation test. The results of the estimation are alsoshown in Table 1.

Comparative Example 2

A polyimide film (product name: Kapton; manufactured by Du Pont-TorayCo., Ltd.) was used as a substrate, and was treated with an oxygenplasma. Then the substrate treated with oxygen plasma was immersed in achloroform solution containing 1 weight % of tetrachlorosilane (SiCl₄)for 10 minutes. The substrate was washed with chloroform and thenimmersed in water. After the substrate was dried, the substrate wasimmersed for an hour in a solution in which the compound represented byFormula V was dissolved in cyclohexane so as to have a concentration of1 weight %. ##STR15##

As a result, a chemically adsorbed film was formed on the surface of thepolyimide film. The resulting chemically adsorbed film was subjected tothe repellency estimation test. The results of the estimation are alsoshown in Table 1.

Furthermore, the surface of the resulting chemically adsorbed film wasanalyzed by an ESCA. The ESCA chart is shown in FIG. 4, and thecomposition of a surface element is shown in Table 2.

Comparative Example 3

A polyimide film (product name: Kapton; manufactured by Du Pont-TorayCo., Ltd.) was used as a substrate, and was immersed for an hour in asolution in which the compound represented by Formula V was dissolved incyclohexane so as to have a concentration of 1 weight % withoutperforming any treatment therefor. ##STR16##

As a result, a chemically adsorbed film was formed on the surface of thepolyimide film. The resulting chemically adsorbed film was subjected tothe repellency estimation test. The results of the estimation are alsoshown in Table 1.

As shown in the results in Table 1, a far larger contact angle can beobtained in all the examples where the contact angles were measured ascompared with the comparative examples. These results prove an extremelyhigh density of a chemically adsorbed film obtained by the productionmethod of the present invention.

Also, as is more apparent from the comparison between the ESCA analysisresults obtained in Example 1 and those obtained in Comparative Example2, the chemically adsorbed film according to the present invention has ahigh density. As shown in FIG. 3, in analyzing the chemically adsorbedfilm of Example 1, a very high spectral peak appears at an energydensity specific to fluorine atoms, whereas, even in analyzing thechemically adsorbed film of Comparative Example 2, there are fewspectral peaks as shown in FIG. 4, which are considerably lower thanthose shown in FIG. 3. In addition, as shown in the results in Table 2,in the composition of the surface element of the chemically adsorbedfilm of Example 1, far larger amounts of F and Si elements are containedin the film as is specific to a chemical absorptive material as comparedwith the results of Comparative Example 2. Therefore, the ESCA analysisresults prove an extremely high density of a chemically adsorbed filmobtained by the production method of the present invention.

Various other modifications will be apparent to and can be readily madeby those skilled in the art without departing from the scope and spiritof this invention. Accordingly, it is not intended that the scope of theclaims appended hereto be limited to the description as set forthherein, but rather that the claims be broadly construed.

What is claimed is:
 1. A method for producing a chemically adsorbed filmcomprising the steps of:irradiating a surface of a polymer substratewith ultraviolet laser light so as to produce a hydrophilic group on thesurface of the polymer substrate, wherein the ultraviolet laser light isselectively irradiated onto a predetermined part of the surface of thepolymer substrate; and contacting the surface of the polymer substrateon which the hydrophilic group is produced with a chemical adsorptionsolution containing a chlorosilane-containing chemical adsorbent and anonaqueous solvent; and reacting the hydrophilic group of the polymersubstrate with a chlorosilyl group of the chlorosilane-containingchemical adsorbent for forming a covalent bond, thereby forming achemically adsorbed film on the surface of the polymer substrate.
 2. Themethod for producing a chemically adsorbed film according to claim 1,wherein the polymer substrate is made of a material selected from thegroup consisting of: polyimide, polycarbonate, polysulfone,polyethyleneterephthalate, polyetheretherketone, polyarylate,polyethersulfone, and polyetherimide.
 3. The method for producing achemically adsorbed film according to claim 1, wherein thechlorosilane-based chemical adsorbent has a fluorocarbon group.
 4. Amethod for producing a chemically adsorbed film comprising the stepsof:irradiating a surface of a polymer substrate with ultraviolet lightincluding a wavelength of about 175 nm or less so as to produce ahydrophilic group on the surface of the polymer substrate, wherein theultraviolet light including a wavelength of about 175 nm or less isselectively irradiated onto a predetermined part of the surface of thepolymer substrate; and contacting the surface of the polymer substrateon which the hydrophilic group is produced with a chemical adsorptionsolution containing a chlorosilane-containing chemical adsorbent and anonaqueous solvent; and reacting the hydrophilic group of the polymersubstrate with a chlorosilyl group of the chlorosilane-containingchemical adsorbent for forming a covalent bond, thereby forming achemically adsorbed film on the surface of the polymer substrate.
 5. Themethod for producing a chemically adsorbed film according to claim 4,wherein the polymer substrate is made of a material selected from thegroup consisting of: polyimide, polycarbonate, polysulfone,polyethyleneterephthalate, polyetheretherketone, polyarylate,polyethersulfone, and polyetherimide.
 6. The method for producing achemically adsorbed film according to claim 4, wherein thechlorosilane-based chemical adsorbent has a fluorocarbon group.
 7. Themethod for producing a chemically adsorbed film according to claim 4,wherein a source of the ultraviolet light including a wavelength ofabout 175 nm or less is a dielectric barrier discharge lamp.
 8. A methodfor producing a chemically adsorbed film comprising the stepsof:irradiating a surface of a polymer substrate with ultraviolet laserlight so as to produce a hydrophilic group on the surface of the polymersubstrate, wherein the ultraviolet laser light is selectively irradiatedonto a predetermined part of the surface of the polymer substrate; andcontacting the surface of the polymer substrate on which the hydrophilicgroup is produced with a chemical adsorption solution containing achlorosilane-containing chemical adsorbent and a nonaqueous solvent; andreacting the hydrophilic group of the polymer substrate with achlorosilyl group of the chlorosilane-containing chemical adsorbent forforming a covalent bond, thereby forming a chemically adsorbed film onthe surface of the polymer substrate, wherein the ultraviolet light isselected from the group consisting of excimer laser light, gas laserlight and YAG laser light.
 9. The method for producing a chemicallyadsorbed film according to claim 8, wherein the ultraviolet laser lightis excimer laser light.